This project is a concerted attempt to study profound hypothermia and its physiologic and metabolic parameters aimed at extending the safe period of circulatory arrest combined with an exploration of methods allowing rapid rewarming without the disadvantages of heparinization and an oxygenator in the system thereby reducing risks as well as total operating time. A second goal is to produce animal models of certain congenital defects for which total "cure" is presently unavailable and to develop and study an appropriate surgical procedure with special attention to free skeletal muscle transplantation in certain conditions with right ventricular hypoplasia requiring chamber enlargement with substance having contractile potential.